function q = Elnppi(mix)

% E[ln p(pi)]

if isfield(mix.varprior, 'a0')
    a0 = mix.varprior.a0;
    a = mix.varposterior.a;

    exp_logmix = dirichletln_exp(a);
    q = dirichletln(exp_logmix, ones(size(a))*a0, 'log');
else
    q = 0;
end
